I am using the formula below. It will only update when I go into the cell and push "enter" to leave the cell.
I think it is due to the iferror
function. It is calculating correcting but I have to hit return.
=sum(iferror(January!B4,0), iferror(February!B4,0), iferror(March!B4,0), iferror(April!B4,0), iferror(May!B4,0), iferror(June!B4,0), iferror(July!B4,0), iferror(August!B4,0), iferror(September!B4,0), iferror(October!B4,0), iferror(November!B4,0), iferror(December!B4,0))